Are second primaries in the lungs and mets the same thing? If not, what is the difference?

Thanks
Cathy

This is an issue for pathologists if they are happening concurrently to name it. If one follows the other time-wise, which sometimes happens in tobacco users the are second primaries. They develop after getting through oral cancer, a second primary. Second primary may also refer to a concurrent cancer of a different origin / etiology. The metastasis of oral cancer to the cervical nodes, to the lungs to the brain, are all known sequential developments and have been seen happing for many decades, those are a spread ( metastasis of the original disease). It is ot a black and white terminology but therse are the various ways that people have described it to me in a clinical setting.

I tend to think that continuation and spread of the existing disease is a met, and anything new that develops is a second primary if the causative agent is different or the timing is not concurrent.

Thanks for this Brian - so am I right in understanding that mets would be cancer spread through the lymphs or blood system where as a second primary would be caused by what ever caused the original cancer, but just be in a different location?

Is it easy for medics to assess the difference in the case of lung tumours identified on scans? The reason why I ask is that the few journal articles I have located on distant mets suggest that the mean time to spread is about 4 years and I just wonder whether that is accurate or whether their figures include second primaries? Also found some quite old articles claiming reasonable survival rates for resection of lung mets, which I found odd as resection very rarely seems a clinical option for mets?

Lung mets these days are resected, or treated with radio frequency ablation and chemo therapy. The naming of all this is secondary to dealing with it. A lung cancer as a second primary is serious. A metastasis of an existing head and neck cancer to the lungs (producing the same number and size of lesions) is a real problem, this is EXPANSION of disease, not a new entity. Spread and further invasion of cancer is a difficult turn around though not impossible in comparison to a new localized cancer. Lob resection is common, and you can live with out large parts of your lungs or even just one. But the issue is why they appeared, and if they came once, they can come again... this is exacerbated by field carcinogenisis such as from tobacco smoking.

A second primary does snot have to have the same causative etiology. Again this may be from large area contamination via tobacco, or a genetic predisposition to cancers in general.